Method and apparatus for transmitting a harq-ack

ABSTRACT

A DL control channel candidate can be decoded. A determination can be made for which DL OFDM symbol the decoded DL control channel candidate is received in. A determination can be made for a DL resource assignment from the decoded DL control channel candidate. Data can be received based on the DL resource assignment. A determination can be made for a time-frequency resource for transmitting a HARQ-ACK at least based on the determined DL OFDM symbol. The HARQ-ACK can be transmitted in the determined time-frequency resource. The transmitted HARQ-ACK can correspond to the received data.

BACKGROUND 1. Field

The present disclosure is directed to a method and apparatus for aphysical uplink control channel for low-latency operation.

2. Introduction

Presently, user equipment, such as wireless communication devices,communicate with other communication devices using wireless signals. Infifth generation (5G) Radio Access Technology (RAT), a User Equipment(UE) may need to perform Downlink (DL) reception and correspondingHybrid Automatic Repeat Request-Acknowledgement (HARQ-ACK) feedbacktransmission, or reception of an Uplink (UL) scheduling grant andcorresponding UL transmission within a slot, in order to supportlow-latency communication. The slot can be a time unit including one ormore symbols, such as 7 or 14 Orthogonal Frequency Division Multiplexing(OFDM), Single Carrier-Frequency Division Multiple Access (SC-FDMA), ordiscrete Fourier Transform-Spread-OFDM (DFT-S-OFDM) symbols.

Physical Uplink Control Channel (PUCCH) with a short duration, such as a1 or 2 symbol duration, can be suitable for low-latency transmission ofHARQ-ACK feedback. To increase the number of UEs in a cell able to use ashort PUCCH, the short PUCCH can be designed to exploit a channelfrequency diversity gain and to flexibly support various sizes of UplinkControl Information (UCI), such as different combinations of HARQ-ACK,Scheduling Request (SR), and limited Channel State Information (CSI).Further, scheduling flexibility for short PUCCH can minimize resourceoverlapping between slot-based UL data channel and short PUCCH.

For low-latency re-transmission, such as re-transmission in animmediately following slot, multiplexing of physical data and controlchannels in the slot can be done such that it can provide both a UE anda network entity, such as a base station, eNodeB (eNB), gNodeB (gNB), orother network entity, with enough processing time, such as for decodingand scheduling.

Larger subcarrier spacing can be employed for short PUCCH thansubcarrier spacing for DL/UL data channels in order to create more shortduration symbols within the reference symbol duration, such as a symbolduration of DL/UL data channel Further, a Demodulation Reference Signal(DMRS) for short PUCCH can be transmitted in the first short symbol,while transmitting UCI content in the second short symbol. Thissubcarrier spacing scaling approach increases UE transmitter complexitywhen short PUCCH and UL data are frequency division multiplexed within aUE, since the UE has to perform Fast Fourier Transform (FFT) of twodifferent sizes. Also, it limits scheduling flexibility of short ULcontrol and UL data, and causes a guard band overhead due to differentnumerology.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the manner in which advantages and features of thedisclosure can be obtained, a description of the disclosure is renderedby reference to specific embodiments thereof which are illustrated inthe appended drawings. These drawings depict only example embodiments ofthe disclosure and are not therefore to be considered to be limiting ofits scope. The drawings may have been simplified for clarity and are notnecessarily drawn to scale.

FIG. 1 is an example block diagram of a system according to a possibleembodiment;

FIG. 2 is an example timing relationship for low-latency operation in aDL-centric slot according to a possible embodiment;

FIG. 3 is an example timing relationship for low-latency operation in anUL-centric slot according to a possible embodiment;

FIG. 4 is an example of resource allocation for DMRS or a sequence-basedmessage;

FIG. 5 is an example for frequency hopping of short PUCCH sub-bandgroups over slots according to a possible embodiment;

FIG. 6 is an example of resource allocation and signaling for shortPUCCH according to a possible embodiment;

FIG. 7 is an example of UL HARQ-ACK transmission symbol determinationbased on OFDM symbol of DL control channel candidate according to apossible embodiment;

FIG. 8 is an example flowchart illustrating the operation of a wirelesscommunication device according to a possible embodiment;

FIG. 9 is an example flowchart illustrating the operation of a wirelesscommunication device according to a possible embodiment;

FIG. 10 is an example flowchart illustrating the operation of a wirelesscommunication device according to a possible embodiment;

FIG. 11 is an example flowchart illustrating the operation of a wirelesscommunication device according to a possible embodiment;

FIG. 12 is an example flowchart illustrating the operation of a wirelesscommunication device according to a possible embodiment;

FIG. 13 is an example flowchart illustrating the operation of a wirelesscommunication device according to a possible embodiment;

FIG. 14 is an example flowchart illustrating the operation of a wirelesscommunication device according to a possible embodiment;

FIG. 15 is an example flowchart illustrating the operation of a wirelesscommunication device according to a possible embodiment; and

FIG. 16 is an example block diagram of an apparatus according to apossible embodiment.

DETAILED DESCRIPTION

Embodiments can provide a method and apparatus for schedulinginformation for a downlink data channel According to a possibleembodiment scheduling information can be transmitted to a user equipmentregarding a downlink data channel in a slot. The scheduling informationcan include information regarding at least a set of allocatedsubcarriers. The downlink data channel can require the user equipment tosend an immediate hybrid automatic repeat request acknowledgementfeedback within the slot. Downlink data can be transmitted using everyx-th subcarrier among the allocated subcarriers in the last symbol ofthe downlink data channel.

According to another possible embodiment, scheduling information can bereceived. The scheduling information can be to transmit a first physicaluplink channel within a slot. The slot can include a plurality ofsymbols. The slot can include the first physical uplink channel and asecond physical uplink channel. The first physical uplink channel can beshorter in duration than the second physical uplink channel One or moreallocated resource blocks for the first physical uplink channel can bedetermined based on a sub-band group and one or more resource blockgroups within the sub-band group. The sub-band group can include one ormore sub-bands. Each sub-band can include one or more resource blockgroups. Each resource block group can include one or more resourceblocks. A resource block can include one or more contiguous resourceelements. The first physical uplink channel can be transmitted in theone or more allocated resource blocks in the slot.

Some embodiments can provide a method to enable low-latencyre-transmission and detailed designs for short PUCCH, such as channelstructure, flexible resource allocation with low Downlink ControlInformation (DCI) signaling overhead, and multiplexing of short PUCCHswith different UCI sizes.

Compared to LTE DL type 0 or type 1 Resource Allocation (RA),embodiments can provide a short PUCCH resource allocation scheme thatcan use less bits to indicate RA, such as 25 bits for LTE DL type 0/1 RAvs. 10 bits for the scheme in the case of 100 Resource Block (RB) systemBandwidth (BW). Since short PUCCH can have a limited range of payloadsizes, such as on/off signaling and 1˜100 bits, scheduling flexibilityfor support of a few RB allocation sizes, such as 6 RBs and 12 RBs, canbe enough, which can lead to signaling overhead reduction. And yet, theproposed RA scheme can support both frequency-selective and frequencydiversity scheduling, and can accommodate wideband short PUCCHtransmission which is required for unlicensed band operation.

In order to support a short PUCCH and/or a short UL data channel of 1symbol based on the same subcarrier spacing as slot-based DL/UL datachannels, a UE can employ an OFDM waveform and Frequency DivisionMultiplexing (FDM) of UCI and DMRS in a short PUCCH. As low-latencyoperation and transmission in short PUCCH mainly target UEs with goodcoverage and/or small propagation delay, OFDM can be used instead ofDFT-S-OFDM.

FIG. 1 is an example block diagram of a system 100 according to apossible embodiment. The system 100 can include a wireless communicationdevice 110, such as a User Equipment (UE), a base station 120, such asan enhanced NodeB (eNB) or fifth generation NodeB (gNB), and a network130. The wireless communication device 110 can be a wireless terminal, aportable wireless communication device, a smartphone, a cellulartelephone, a flip phone, a personal digital assistant, a personalcomputer, a selective call receiver, a tablet computer, a laptopcomputer, or any other device that is capable of sending and receivingcommunication signals on a wireless network.

The network 130 can include any type of network that is capable ofsending and receiving wireless communication signals. For example, thenetwork 130 can include a wireless communication network, a cellulartelephone network, a Time Division Multiple Access (TDMA)-based network,a Code Division Multiple Access (CDMA)-based network, an OrthogonalFrequency Division Multiple Access (OFDMA)-based network, a Long TermEvolution (LTE) network, a 3rd Generation Partnership Project(3GPP)-based network, a satellite communications network, a highaltitude platform network, the Internet, and/or other communicationsnetworks. The network 130 can include various network entities (notshown).

According to a possible embodiment, a Network Entity (NE), such as thebase station 120 or other entity on the network 130, can transmit DLdata by using every x-th, such as x=2, subcarrier among allocatedsubcarriers for the last symbol of a DL data channel, if the DL datachannel in a slot requires a UE to send immediate HARQ-ACK feedback onthe same slot. Mapping data into every x-th subcarrier can result inx-times repetition of time-domain samples within the last OFDM symbolduration of the DL data channel. When receiving the last symbol of theDL data channel, the UE can receive only first part of time-domainsamples out of multiple repeated samples. The UE can demodulate, combinethe multiple repeated samples, and decode the data channel by employingFFT with possibly reduced FFT size, such as a size reduced by a factorof x. Since the UE receiving time for the last symbol of the datachannel can be reduced, the remaining time can be exploited for UEprocessing time, such as for decoding DL data and preparation ofHARQ-ACK feedback transmission.

Some embodiments can create a time budget for UE processing from the DLregion in a UE-specific manner, without increasing UE Tx/Rx complexity.The value x can be set by the network, dependent on UE capability.Furthermore, there may be no impact on a DL data channel that does notrequire immediate HARQ-ACK feedback.

FIG. 2 is an example illustration 200 of a timing relationship forlow-latency operation in a DL-centric slot according to a possibleembodiment. For example, the illustration 200 shows a timingrelationship among a base station, such as a gNodeB (gNB), and UEtransmission/reception (Tx/Rx). The timing gap T_(o) can be created atthe end of a slot via the UE's transmit timing advance, in order toprovide gNB with processing time and Rx-to-Tx switching time. A gapduration of approximately equal to the symbol duration T_(s) can be usedto accommodate round trip delay (2T_(p)) between the UE and the gNB, UERx-to-Tx switching time, and gNB processing and Rx-to-Tx switching time.For example, UE Rx-to-Tx+(gNB processing+Rx-to-Tx) can be T_(o) and thetotal can be 2T_(p)+T_(o). In order to provide at least a half-symbol UEprocessing time, the gNB can transmit DL data on every other subcarrierfor the last DL symbol, and the UE can receive samples corresponding toa first half-symbol and starts demodulation. Mapping DL data on everyother subcarrier may only be applied to a DL data channel for a UErequiring immediate HARQ-ACK feedback.

FIG. 3 is an example illustration 300 of a timing relationship forlow-latency operation in an UL-centric slot according to a possibleembodiment. The illustration 300 can show that placing an UL DMRS in thebeginning of an UL data channel can provide a time budget for UE todecode a UL scheduling grant message, such as if the UL DMRS is known tobe transmitted in a predetermined location in frequency domain notdependent on the UL scheduling grant message, and to prepare an UL datachannel.

According to a possible embodiment, a UE can determine a resource forshort PUCCH based on an indicated sub-band group and indicated ResourceBlock Groups (RBGs) within the indicated sub-band group. A sub-bandgroup can include of one or more sub-bands evenly distributed over asystem Bandwidth (BW) and/or a UE's operating bandwidth, and more thanone sub-band group can be defined within the system BW and/or UE'soperating BW. Each sub-band can include one or more RBGs, and each RBGcan include one or more contiguous Resource Blocks (RBs), such as 3 RBs.In one example, a resource block can include 12 subcarriers, orequivalently, 12 Resource Elements (REs).

FIG. 4 is an example illustration 400 of resource allocation for DMRS ora sequence-based message according to a possible embodiment. Since DMRScan be multiplexed with UCI within a RB as shown in the illustration400, RBG-level resource aggregation for short PUCCH can be beneficial toobtain reliable channel and interference estimates, compared to RB-levelresource aggregation. To support a range of UCI sizes, such as 10-100bits, a limited number of RBG aggregation levels, such as 1, 2, 4, and 8RBG aggregations, can be defined.

According to a possible embodiment, the NE or gNB can semi-staticallyconfigure a UE with a UE-specific sub-band group via a higher-layersignaling, and can dynamically indicate allocated RBGs within theconfigured UE-specific sub-band group via DCI. According to anotherpossible embodiment, both the sub-band group and allocated RBGs withinthe sub-band group can be dynamically signaled.

FIG. 5 is an example illustration 500 of frequency hopping of shortPUCCH sub-band groups over slots according to a possible embodiment. Forexample, the system transmission bandwidth can be 100 RB and edge 2 RBsof each side of a transmission band can be reserved for long PUCCH, suchas UCI transmission spanning over an UL-slot or an UL region of anUL-centric slot, or for UL data. Each sub-band can include 2 RBGs, andeach RBG can include 3 RBs. 16 sub-bands can exist in the system, and 4sub-band groups, such as 4 sub-bands or 8 RBGs per sub-band group, canbe defined. For dynamic signaling of short PUCCH RA, 2 bits can be usedfor selection of sub-band group, and a bitmap of 8 bits can be used toindicate selected RBGs within the selected sub-band group.

FIG. 6 is an example illustration 600 of resource allocation andsignaling for short PUCCH according to a possible embodiment. Theillustration 600 can show short PUCCH resource allocation with 2 RBGaggregation, and each bit in a bitmap can indicate a resource assignmentof a corresponding RBG. In an alternate embodiment, signaling of theselected RBGs can include indication of the RBG aggregation level, suchas the number of RBGs, and position of the first selected RBG. Theposition of the other selected RBGs can be equally spaced with an offsetwhich can be determined as the number of RBGs per sub-band groupnormalized by the RBG aggregation level.

According to a possible embodiment, a NE can semi-statically configure,via higher-layer signaling of a sub-band group index and RBG bitmap, aUE with a UE-specific resource for a short PUCCH carrying a SchedulingRequest (SR). The higher layer can be higher than a physical layer.Frequency-hopping of the sub-band groups over slots, as shown in theillustration 500, can provide frequency diversity and interferencerandomization for semi-statically configured SR resources.

Additionally, a UE can receive an indication of a selected DMRS patternfor a short PUCCH. According to a possible embodiment, a UE can besemi-statically configured with a DMRS pattern based on UE/NEbeamforming capabilities and long-term channel characteristics, such asmaximum delay spread. Alternatively, the NE can dynamically indicate theDMRS pattern in a UCI scheduling grant message, depending on UCI sizesin a short PUCCH. For example, a short PUCCH with a small UCI size, suchas 10 bits, can be configured with high density DMRS pattern as shown bythe DMRS pattern 1 in the illustration 400, while short PUCCH with alarge UCI size, such as 40 bits, can be configured with low density DMRSpattern as shown by the DMRS pattern 2 in the illustration 400.

The resource allocation scheme described above can be used for RA of ashort duration UL data channel, such as 1-2 symbol non-slot based datatransmission, in the short UL control region.

Short PUCCH can carry SR via on/off signaling, 1 or 2 HARQ-ACK bits, or10˜100 bits including CSI and HARQ-ACK. For 10-100 bits UCI, channelcoded bits can be mapped to modulation symbols, and the resultingmodulation symbols can be transmitted on non-DMRS REs. DMRS basedcoherent demodulation and decoding can be performed at a receiver. BothSR and 1-2 HARQ-ACK bits can be transmitted via a sequence-basedmessage, and the receiver can perform sequence detection for decoding. Abase Zadoff-Chu (ZC) sequence and sequences resulting from time-domaincyclic shifts of the base ZC sequence can be used for DMRS andsequence-based messages. A NE can configure a UE with RBs or RBGs and asequence for SR semi-statically, and can dynamically allocate RBs orRBGs and 2 or 4 sequences for 1 or 2 HARQ-ACK bits.

As short PUCCH can employ an OFDM waveform and can be applicable tonon-power limited UEs, a UE can transmit multiple short PUCCHs carryingdifferent UCI simultaneously. Moreover, HARQ-ACK bits and SR can betransmitted via separate sequences. Thus, the following short PUCCHformat can be defined:

Format 1/1a/1b: SR, 1-bit HARQ-ACK, 2-bit HARQ-ACK, respectively

Format 2: 10-100 bits, combination of CSI and HARQ-ACK

According to a possible embodiment, an RB-length, such as a 12subcarrier/RE, sequence, can be used for short PUCCH format 1/1a/1b, andcan be mapped to every RE of an allocated RB and repeated over all theallocated RBs to achieve an SNR processing gain. In this case, RBGsallocated for short PUCCH format 1/1a/1b may not be used for short PUCCHformat 2. However, a larger number of cyclic shifts of a base sequence,such as up to 12 cyclic shifts, equivalently a larger number oforthogonal sequences can be supported, such as multiplexed in a givenRB, since the sequence can be mapped to contiguous REs. In addition, theSNR gain can be dependent on the total number of allocated RBs (N_(RB))i.e. SNR gain (dB)=10 log₁₀ N_(RB).

According to another possible embodiment, sequences for short PUCCHformat 1/1a/1b can be transmitted on REs reserved for DMRS. For example,DMRS pattern 1 in the illustration 400 can result in 12 DMRS REs withinan RBG, such as 3 RBs, and a length-12 ZC sequence or its cyclic shiftedversion for short PUCCH format 1/1a/1b can be mapped to DMRS REs of theRBG. An SNR processing gain can be obtained via RBG-level aggregation,and can be dependent on the number of aggregated RBGs, (N_(RBG)), i.e.SNR gain (dB)=10 log₁₀ N_(RBG). In this case, a given RBG can be sharedby short PUCCH format 1/1a/1b and format 2. If a short UL data channelin the short UL control region uses the same DMRS pattern and RBG-levelresource allocation structure as short PUCCH, short PUCCH format 1/1a/1bcan be multiplexed with short UL data channel in a given RBG.

However, the number of allowed cyclic shifts, such as the maximum numberof orthogonally multiplexed sequences, of a base sequence can decreasedue to increased subcarrier spacing between two adjacent REs used forshort PUCCH format 1/1a/1b. For example, up to 4 cyclic shifts of a baseZC sequence can be supported when short PUCCH format 1/1a/1b resourcemapping is based on DMRS pattern 1 in the illustration 400. Fourorthogonal sequences may be required for a UE in a given RBG torepresent 2 bits for short PUCCH format 1b. According to a possibleembodiment, a given UE can transmit a short UL data channel and a shortPUCCH format 1b together in one or more allocated RBGs, and a networkcan coherently demodulate the received UL data channel by detecting asequence of short PUCCH format 1b and performing channel estimationbased on the detected sequence. According to another possibleembodiment, the UE can use two mutually exclusive subsets of allocatedRBGs to transmit short PUCCH format 1b, where each subset of theallocated RBGs can carry 1-bit HARQ-ACK based on 2 orthogonal sequencesand selection of one subset of the allocated RBGs can indicate another1-bit HARQ-ACK.

The symbol/slot in which the UE transmits HARQ/ACK using PUCCH or shortPUCCH can depend on the DL search space configured for the UE. Forexample, the UE can be configured to monitor a set of downlink controlchannel candidates. Monitoring can imply attempting to decode. The setof control channel candidates monitored by the UE can span a set of OFDMsymbols. The set of OFDM symbols for DL control channel monitoring canbe typically located in the beginning of a slot/mini-slot. In oneexample, the slot can include 14 OFDM/SC-FDMA symbols and the mini-slotor non-slot can include from 1 to 13 OFDM/SC-FDMA symbols. The controlchannel candidates can be mapped to physical resource elements, such asREs or groups of REs, such as REGs, or groups of REGs/REs, such asControl Channel Elements (CCEs), in the set of OFDM symbols according todifferent implementations.

According to a first example implementation, each control channelcandidate can be mapped to REs within a single OFDM symbol within theset of OFDM symbols, but different candidates in the set can belong todifferent OFDM symbols in the set of OFDM symbols. For example, if 6control channel candidates c1, c2, . . . , c6 are monitored in 3 OFDMsymbols s1, s2, s3, then candidates c1, c2 can be mapped entirely withinOFDM symbol s1; candidates c3, c4 can be mapped entirely within OFDMsymbol s2; and candidates c5, c6 can be mapped entirely within OFDMsymbol s3.

FIG. 7 is an example illustration 700 of UL HARQ-ACK transmission symboldetermination based on the OFDM symbol of DL control channel candidateaccording to a possible embodiment. Considering the possibilitiesdiscussed above for receiving control signaling, if the control channelcandidate is mapped according to the first implementation, such asentirely within a symbol of a set of symbols, the UL OFDM/SC-FDMAsymbol/slot position for the HARQ-ACK corresponding to the controlchannel candidate, such as the HARQ-ACK corresponding to the datadecoded based on the DL resource assignment determined from the decodedcontrol channel candidate, can be determined based on the OFDM symbol inwhich all the REs of the control channel candidate are located. Forexample, if DL control channel candidates c1, c2 are monitored in OFDMsymbol s1, candidates c3, c4 are monitored in OFDM symbol s2, andcandidates c5, c6 are monitored in OFDM symbol s3 of slot x according tothe example described for the first example implementation above. If theUE determines its DL assignment by decoding candidate c1 or c2, such asthose present in OFDM symbol s1, it can transmit the correspondingHARQ-ACK in OFDM symbol s13 of slot x. If the UE determines its DLassignment by decoding a candidate, such as c3, c4, in a later symbol,such as symbol s2 or s3, it can transmit the corresponding HARQ-ACK inOFDM symbol s14 of slot x. Hence, the UL OFDM symbol in which HARQ-ACKis sent can be determined based on the DL OFDM symbol in which thecorresponding control channel candidate is decoded. This example is alsoillustrated in the illustration 700. In another example, if the UEdetermines its DL assignment by decoding candidate c1, c2, c3, or c4,such as those present in OFDM symbol s1 or s2, it can transmit acorresponding HARQ-ACK in OFDM symbol s14 of slot x. If the UEdetermines its DL assignment by decoding candidate c5 or c6, such asthose present in OFDM symbol s3, it can transmit a correspondingHARQ-ACK in OFDM symbol s14 of slot x+1. Hence, the UL slot in whichHARQ-ACK is sent can be determined based on the DL OFDM symbol index inwhich the corresponding control channel candidate is decoded.

According to a second example implementation, each control channelcandidate can be mapped to REs within multiple OFDM symbols within theset of OFDM symbols. For example, if 6 control channel candidates c1,c2, . . . c6 are monitored in 4 OFDM symbols s1, s2, s3, s4, then c1, c2can be mapped to REs spanning OFDM symbols s1, s2. Similarly, c3, c4 canbe mapped to REs spanning OFDM symbols s3, s4, while c5, c6 can bemapped to REs spanning all four OFDM symbols s1, s2, s3, s4.

As discussed above, if the UE successfully decodes a control channelcandidate, determines a DL resource assignment from the decodedcandidate, and decodes data, such as on a PDSCH, using the DL resourceassignment, the UL OFDM/SC-FDMA symbol/slot in which the UE sendsHARQ-ACK, such as on a PUCCH/short PUCCH, corresponding to the decodeddata can vary based on the DL OFDM symbol in which the correspondingcontrol channel candidate is decoded.

If the control channel candidate is mapped according to the secondexample implementation, such as within multiple symbols of a set ofsymbols, the HARQ-ACK symbol/slot location corresponding to the controlchannel candidate, such as the HARQ-ACK corresponding to the datadecoded based on the DL resource assignment determined from the decodedcontrol channel candidate, can be determined based on the last OFDMsymbol in which the REs of the control channel candidate are located.For example, if the REs of a candidate c1 are mapped to OFDM symbols s1,s2 of slot x, then a corresponding HARQ-ACK can be sent in UL OFDMsymbol s13 of slot x. If the REs of a candidate c2 are mapped to OFDMsymbols s2, s3 of slot x, then corresponding HARQ-ACK can be sent in ULOFDM symbol s14 of slot x.

In the above examples, each DL or UL slot is assumed to have 14 OFDMsymbols (s1, s2, . . . s14) with symbol s1 in the beginning of the slotand symbol s14 at the end of the slot. It should be noted that the OFDMsymbol corresponding to the DL control channel candidate, such as theOFDM symbol in which all REs of the candidate are present according tothe first implementation or the last OFDM symbol in which the REs of acandidate are mapped according to the second implementation, can be oneof multiple criteria used in determining the resource used for HARQ-ACKtransmission for data associated with the DL assignment given by thecontrol channel candidate. For example, the UE can use the DL OFDMsymbol corresponding to the decoded DL control channel candidate todetermine a UL OFDM symbol/slot for transmitting a correspondingHARQ-ACK, such as a HARQ-ACK corresponding to the data decoded based onthe DL resource assignment determined from the decoded control channelcandidate, and the UE can use an RB index, such as the lowest RB index,from the RBs given in the DL assignment to determine a HARQ-ACK resourceindex within the determined UL OFDM symbol/slot; and the UE can transmitHARQ-ACK in a HARQ-ACK resource with the determined HARQ-ACK index inthe determined UL OFDM symbol/slot.

In another example, the UE can use the DL OFDM symbol corresponding tothe decoded DL control channel candidate to determine a UL OFDMsymbol/slot for transmitting corresponding HARQ-ACK, such as theHARQ-ACK corresponding to the data decoded based on the DL resourceassignment determined from the decoded control channel candidate, andthe UE can use a CCE index, such as the lowest CCE index, of the decodedcontrol channel candidate to determine a HARQ-ACK resource index withinthe determined UL OFDM symbol/slot; and the UE can transmit HARQ-ACK ina HARQ-ACK resource with the determined HARQ-ACK index in the determinedUL OFDM symbol/slot.

The approaches described above can be useful reducing UE complexity bygiving the UE enough processing time to decode data and send HARQ-ACKbased on when the UE finishes its control channel decoding. For example,if the control channel candidate is decoded early because it is sent inan earlier DL OFDM symbol, a corresponding HARQ-ACK can be sent in anearlier UL OFDM symbol, and if the control channel candidate is decodedlater because it is sent in an later DL OFDM symbol, a correspondingHARQ-ACK can be sent in a later UL OFDM symbol without forcing the UE toimplement a tighter HARQ processing timeline based on the last possibleDL OFDM symbol for control channel decoding and the first possible ULOFDM symbol/slot for corresponding HARQ-ACK transmission.

Another reason for delay in DL control channel decoding can be thenumber of control channel candidates that the UE is expected to monitor.To address this issue, the UL OFDM symbol/slot in which the UE sendsHARQ-ACK can be varied based on the number of control channel candidatesthat the UE is expected to monitor. For example, if the UE monitors asmall number, such as n1=4, of control channel candidates, thecorresponding HARQ-ACK for a successfully decoded control channelcandidate, such as a HARQ-ACK corresponding to the data decoded based onthe DL resource assignment determined from the decoded control channelcandidate, can be sent in an earlier UL symbol/slot, such as in symbol14 of slot x. If the UE monitors a large number, such as n2=32, ofcontrol channel candidates, the corresponding HARQ-ACK for asuccessfully decoded control channel candidate can be sent in a later ULsymbol/slot, such as in symbol 14 of slot x+1. The number of controlchannel candidates monitored by the UE can be indicated via a higherlayer, such as Radio Resource Control (RRC) or Medium Access Control(MAC) layer, signaling, where the higher layer is higher than thephysical layer. The number of control channel candidates monitored bythe UE can be a number of control channel candidates monitored by the UEwithin a slot/mini-slot.

In the present disclosure, a “UL OFDM symbol” can also be a “ULDFT-S-OFDM symbol” or “UL SC-FDMA symbol.”

Some embodiments below can provide a time budget for low-latencyoperation.

FIG. 8 is an example flowchart 800 illustrating the operation of awireless communication device, such as a network entity, according to apossible embodiment. The network entity can be a base station, such asan eNB, a gNB, or other base station, can be an access point, can be anetwork controller, can be a mobility management entity, or can be anyother network entity or combination of network entities that performs DLtransmission in a carrier frequency.

At 810, scheduling information can be transmitted to a UE regarding a DLdata channel in a slot. The scheduling information can includeinformation regarding at least a set of allocated subcarriers. The DLdata channel can require the UE to send an immediate HARQ-ACK feedbackwithin the slot. The scheduling information can be determined by acontroller at the network entity or at another network entity and can betransmitted in a PDCCH. The DL data channel can be a PDSCH.

At 820, DL data can be transmitted using every x-th subcarrier among theallocated subcarriers in the last symbol of the DL data channel. A valueof x can be greater than one. For example, when x is 2, the DL data canbe transmitted every second subcarrier among the allocated subcarriersin the last symbol of the DL data channel. As a further example, everyx-th subcarrier can be every subcarrier that skips a number ofsubcarriers. A value of x can be set based on UE processing capabilityand the value of x can be indicated to the UE.

The UE can receive only a first part of time-domain samples out of xrepeated samples in the last symbol of the DL data channel. The UE candemodulate and decode the DL data channel by employing a first FastFourier Transform (FFT) size in symbols except for the last symbol and asecond FFT size in the last symbol. The second FFT size can be smallerthan the first FFT size by a factor of a value of x.

One OFDM symbol can include N_CP (cyclic prefix) samples and N samplesin time, sequentially. If the N/x data is mapped to every x-thsubcarrier in the frequency domain at a gNB transmitter, the resultingOFDM symbol before appending cyclic prefix can have x repetitions of N/xsamples. If the UE receiver receives CP and the first N/x samples,removes CP, and applies FFT of size N/x, the resulting FFT output cancorrespond to N/x subcarriers carrying N/x data.

FIG. 9 is an example flowchart 900 illustrating the operation of awireless communication device, such as the UE 110 or any other terminalthat sends and receives wireless communication signals over a wirelesswide area network, according to a possible embodiment. At 910,scheduling information can be received from a network entity. Thescheduling information can regard a DL data channel in a slot. Thescheduling information can include information regarding at least a setof allocated subcarriers. The DL data channel can require the UE to sendan immediate HARQ-ACK feedback within the slot.

At 920, DL data can be received using every x-th subcarrier among theallocated subcarriers in the last symbol of the DL data channel. Thevalue of x can be greater than one. For example, every x-th subcarriercan be every subcarrier that skips a given number of subcarriers. Thevalue of x can be received from a network entity. The value of x can beset based on UE processing capability.

Only a first part of time-domain samples out of x repeated samples canbe received in the last symbol of the DL data channel. The DL datachannel can be demodulated and decoded by employing a first FFT size insymbols except for the last symbol and a second FFT size in the lastsymbol. The second FFT size can be smaller than the first FFT size by afactor of x. Remaining time after receiving only a first part oftime-domain samples in the last symbol can be used for processing timeof decoding DL data. At 930, a HARQ-ACK can be transmitted in responseto receiving the DL data.

FIG. 10 is an example flowchart 1000 illustrating the operation of awireless communication device, such as the UE 110 or any other terminalthat transmits and receives wireless communication signals over awireless wide area network, according to a possible embodiment. Forexample, the flowchart 1000 can be for a method in a UE to performuplink transmission in a carrier frequency.

At 1010, scheduling information can be received. The schedulinginformation can schedule at least one resource for the UE to transmitthe first uplink channel. For example, the scheduling information caninclude information for a scheduling request transmission, informationfor transmitting HARQ-ACK, and/or other information. A SchedulingRequest (SR) can be part of Uplink Control Information (UCI) from a UEto a network, can be semi-statically configured, can be 1 RB, and/or canbe in a sub-band group.

Receiving scheduling information can include semi-statically receivingan indication of the sub-band group via a higher-layer signaling anddynamically receiving an indication of allocated RBGs within theindicated sub-band group via DCI. Receiving scheduling information canalso include semi-statically receiving both an indication of thesub-band group and an indication of allocated RBGs within the indicatedsub-band group via a higher-layer signaling. Receiving schedulinginformation can also include dynamically receiving both an indication ofthe sub-band group and an indication of allocated RBGs within theindicated sub-band group via DCI.

The scheduling information can indicate the sub-band group and the oneor more RBGs within the sub-band group. The sub-band group can beindicated by being transmitted as part of DCI, can be indicated by usingan RRC message, can be indicated via other layers higher than a physicallayer, or can be otherwise indicated, such as by a network entity.According to a possible implementation, resource allocation for thefirst physical uplink channel can allow a set of RBG aggregation levels.The set of RBG aggregation levels can include 1, 2, 4, and 8 RBG's. Forexample, a short PUCCH resource allocation can allocate resources to theshort PUCCH and the allocated resources can include aggregated RBG'sthat can be aggregated in a group of 1, 2, 4, and/or 8 RBG's. Theaggregation of RBG's may or may not be contiguous.

The one or more sub-bands in the sub-band group can be distributed overa UE's configured operating BW. The UE's configured operating BW caninclude at least one sub-band group. A system BW including the UE'sconfigured operating BW can include at least one sub-band group. Forexample, the sub-bands in the sub-band group can be evenly andnon-contiguously distributed over the system BW and/or the UE'sconfigured BW. As a further example, the sub-band group can include ofone or more sub-bands evenly distributed over a UE's operatingbandwidth, and more than one sub-band group can be defined within theUE's operating BW and/or a system BW including the UE's operating BW.

Sub-band groups of the at least one sub-band group can be frequencyhopped in different slots. For example, at least one sub-band group canbe in a first sub-band of frequencies in one slot and can be in a secondsub-band of frequencies in a next slot.

The scheduling information can be for transmitting a first physicaluplink channel within a slot. The first physical uplink channel canspan, at least one symbol, such as at least one of a last three symbols,of the slot. For example, the first physical uplink channel can be aPhysical Uplink Shared Channel (PUSCH) and/or a Physical Uplink ControlChannel (PUCCH) that spans up to two symbols of the slot. Time-frequencyresources of the first physical uplink channel can be shared betweenmultiple UE's.

The slot can include a plurality of symbols, such as 2, 3, 7, 14 or anynumber of symbols, and the first physical uplink channel can span atleast one of two symbols of the slot. The slot can include the firstphysical uplink channel and can also include a second physical uplinkchannel. The first physical uplink channel can be shorter in durationthan the second physical uplink channel.

At 1020, one or more allocated RBs for the first physical uplink channelcan be determined based on a sub-band group and one or more RBGs withinthe sub-band group. The sub-band group can include one or moresub-bands. Each sub-band can include one or more RBGs. Each RBG caninclude one or more RBs. A RB can include one or more contiguous REs inthe frequency domain. For example, a RB can include one or morecontiguous subcarriers where each subcarrier can include an RE. Also,number of DL control channel candidates belonging to a set of controlchannel decoding candidates can be determined and the time-frequencyresource for a PUCCH carrying the HARQ-ACK can be determined in adetermined one or more allocated resource blocks, such as in 1020 of theflowchart 1000, at least based on the number of DL control channeldecoding candidates belonging to the set of control channel decodingcandidates.

A slot can include a first PUCCH and a second PUCCH. The first PUCCH canbe shorter in duration than the second PUCCH. The first physical uplinkchannel can the first PUCCH. The first PUCCH can have one of followingshort PUCCH formats based on UCI type and sizes:

-   -   Format 1: SR,    -   Format 1a: 1-bit HARQ-ACK,    -   Format 1b: 2-bits HARQ-ACK, or    -   Format 2: combination of CSI and HARQ-ACK bits.

A sequence-based message can be used for SR, 1-bit HARQ-ACK, and 2-bitHARQ-ACK transmitted on the first physical uplink channel. An RB-lengthsequence used for SR, 1-bit HARQ-ACK, and 2-bit HARQ-ACK, can be mappedto every RE of an allocated RB. Also, a sequence used for the SR, the1-bit HARQ-ACK, and the 2-bit HARQ-ACK can be transmitted on REsreserved for DMRS in at least one allocated RBG and/or allocated RB. Abase sequence and sequences resulting from time-domain cyclic shifts ofthe base sequence can be used for DMRS and sequence-based messages.

At 1030, the first physical uplink channel can be transmitted in thedetermined one or more allocated RBs in the slot. The first physicaluplink channel can be transmitted with an OFDM waveform and a DMRS canbe frequency-division multiplexed with at least one UL data and/or UCIin the first physical uplink channel. Multiple short PUCCHs carryingdifferent UCI can be transmitted simultaneously. According to a possibleimplementation, the first physical uplink channel can be transmittedwith 2-bits HARQ-ACK that is indicated based on selection of oneselected from two mutually exclusive subsets of allocated RBs, and basedon selection of one selected from two allocated sequences.

According to another possible implementation, the slot can include afirst PUCCH and a second PUCCH. The first PUCCH can be shorter induration than the second PUCCH. The slot can also include a first PUSCHand a second PUSCH. The first PUSCH can be shorter in duration than thesecond PUSCH. The first physical uplink channel can be at least oneselected from the first PUCCH and the first PUSCH. The first PUCCH andthe first PUSCH can be transmitted together in at least one allocatedRBGs and/or allocated RBs, wherein the first PUCCH can include thesequence used for the SR, the 1-bit HARQ-ACK, and the 2-bit HARQ-ACK.

FIG. 11 is an example flowchart 1100 illustrating the operation of awireless communication device, such as a network entity, according to apossible embodiment. The network entity can be a base station, such asthe base station 120, an access point, a network controller, a mobilitymanagement entity, or any other network entity or combination of networkentities that transmit scheduling information over a wireless wide areanetwork.

At 1110, scheduling information can be transmitted to a UE. Thescheduling information can schedule the UE to transmit a first physicaluplink channel within a slot. The slot can include a plurality ofsymbols. The slot can also include the first physical uplink channel anda second physical uplink channel. The first physical uplink channel canbe shorter in duration than the second physical uplink channel. Thefirst physical uplink channel can span at least one of a last threesymbols of the slot.

At 1120, the first physical uplink channel can be received in the one ormore allocated RBs in the slot. The one or more allocated RBs for thefirst physical uplink channel can be determined based on an indicatedsub-band group and one or more indicated RBGs within the indicatedsub-band group. The sub-band group can include one or more sub-bands.Each sub-band can include one or more RBGs. Each RBG can include one ormore RBs. A RB can include one or more contiguous REs. The one or moreallocated RBs for the first physical uplink channel can be determinedbased on an indicated sub-band group and one or more indicated RBGswithin the indicated sub-band group.

FIG. 12 is an example flowchart 1200 illustrating the operation of awireless communication device, such as the UE 110 or any other terminalthat transmits and receives wireless communication signals over awireless wide area network, according to a possible embodiment. At 1210,a DL control channel candidate can be decoded. Decoding can includedecoding the DL control channel candidate in a slot.

At 1220, a determination can be made as to which DL OFDM symbol thedecoded DL control channel candidate is received in. For example, the DLOFDM symbol can be determined to be received in the slot in which the DLcontrol channel candidate is decoded. According to a possibleimplementation, each control channel candidate can be mapped to REswithin multiple OFDM symbols. For example, the DL control channelcandidate can be one of a plurality of DL control channel candidates,where each DL control channel candidate can be mapped to REs withinmultiple OFDM symbols and a last DL OFDM symbol of multiple OFDM symbolscorresponding to the decoded DL control channel candidate can bedetermined to be the DL OFDM symbol.

At 1230, a DL resource assignment can be determined from the decoded DLcontrol channel candidate. At 1240, data can be received based on the DLresource assignment.

At 1250, a time-frequency resource for transmitting a HARQ-ACK can bedetermined at least based on the determined DL OFDM symbol. For example,an UL OFDM symbol in the slot for transmitting HARQ-ACK can bedetermined at least based on the determined DL OFDM symbol. According toanother possible implementation, the time-frequency resource fortransmitting a HARQ-ACK can be determined in the one or more allocatedresource blocks determined in 1020 of the flowchart 1000.

According to a possible implementation, a number of DL control channelcandidates belonging to a set of control channel decoding candidates canbe determined and a time-frequency resource for a PUCCH carrying theHARQ-ACK can be determined at least based on the number of DL controlchannel decoding candidates belonging to the set of control channeldecoding candidates.

At 1260, the HARQ-ACK can be transmitted in the determinedtime-frequency resource. For example, the HARQ-ACK can be transmitted inthe determined UL OFDM symbol. The transmitted HARQ-ACK can correspondto the received data. According to a possible implementation, the datacan be received in a resource assigned by the DL resource assignment andthe HARQ-ACK can be transmitted in the determined time-frequencyresource in response to receiving the data based on the DL resourceassignment. According to another possible implementation, the, theHARQ-ACK can be transmitted in the determined time-frequency resource inthe determined one or more allocated resource blocks.

According to a possible embodiment, the DL control channel candidate canbe decoded in a slot. The DL OFDM symbol can be determined to bereceived in the slot in which the DL control channel candidate isdecoded. Determining a time-frequency resource for transmitting HARQ-ACKat least based on the determined DL OFDM symbol further can includedetermining a subsequent slot for transmitting HARQ-ACK at least basedon the determined DL OFDM symbol. The HARQ-ACK can be transmitted in thedetermined subsequent slot, where the transmitted HARQ-ACK cancorrespond to the received data.

According to another possible embodiment, determining a DL OFDM symbolthe decoded DL control candidate is received in can include determiningthe DL OFDM symbol from one of a first DL OFDM symbol and a second OFDMDL symbol corresponding to the decoded DL control channel candidate. Thefirst OFDM symbol can occur earlier in time than the second OFDM symbol.Transmitting the HARQ-ACK can include transmitting the HARQ-ACK in afirst time-frequency resource if the determined DL OFDM symbol is thefirst DL OFDM symbol. Transmitting the HARQ-ACK can also includetransmitting the HARQ-ACK in a second time-frequency resource if thedetermined DL OFDM symbol is the second DL OFDM symbol. The firsttime-frequency resource can occur earlier in time than the secondtime-frequency resource. According to a possible implementation, thefirst time-frequency resource can be within a first UL symbol in a slotand the second time-frequency resource can be within a second UL symbolin the slot. The first UL symbol can occur before the second UL symbol.According to another possible implementation, the first time-frequencyresource can be within a first slot and the second time-frequencyresource can be within a second slot. The first slot can occur beforethe second slot. According to another possible implementation, a RBindex for receiving data can be determined from the DL resourceassignment and the time-frequency resource for transmitting HARQ-ACK canbe determined based on the determined RB index. According to anotherpossible implementation, a CCE index corresponding to the DL controlchannel candidate can be determined and the time-frequency resource fortransmitting HARQ-ACK can be determined based on the determined CCEindex.

FIG. 13 is an example flowchart 1300 illustrating the operation of awireless communication device, such as a network entity, according to apossible embodiment. The network entity can be a base station, an accesspoint, a network controller, a mobility management entity, or any othernetwork entity or combination of network entities that transmit acontrol channel over a wireless wide area communication network to auser equipment.

At 1310, at least one DL OFDM symbol can be selected from a plurality ofDL OFDM symbols for transmitting a DL OFDM control channel. The DL OFDMcontrol channel can be a PDCCH or any other DL OFDM control channel. Theat least one DL OFDM symbol can be selected from a plurality of DL OFDMsymbols for transmitting a DL OFDM control channel in the slot.According to another possible implementation, the at least one DL OFDMsymbol can be selected from one of a first DL OFDM symbol and a secondOFDM DL symbol corresponding to the transmitted DL control channel. Thefirst OFDM symbol can occur earlier in time than the second OFDM symbol.

At 1320, the DL OFDM control channel can be transmitted on the selectedat least one DL OFDM symbol. According to a possible implementation, theDL control channel can be transmitted on the selected at least one DLOFDM symbol in a slot.

At 1330, data can be transmitted to a UE. At 1340, a HARQ-ACK can bereceived from the UE in a time-frequency resource. The HARQ-ACK cancorrespond to the transmitted data. The time-frequency resource can atleast be based on the selected at least one DL OFDM symbol. According toa possible implementation, a HARQ-ACK can be received from the UE in aUL OFDM symbol in the slot, where the HARQ-ACK can correspond to thetransmitted data, and where the UL OFDM symbol can be at least based onthe selected at least one DL OFDM symbol. According to another possibleimplementation, a HARQ-ACK can be received from the UE in a UL OFDMsymbol in a subsequent slot, where the HARQ-ACK can correspond to thetransmitted data, and where the subsequent slot can be at least based onthe selected at least one DL OFDM symbol.

According to another possible implementation, the HARQ-ACK can bereceived in a first time-frequency resource if the selected DL OFDMsymbol is the first DL OFDM symbol and the HARQ-ACK can be received in asecond time-frequency resource if the selected DL OFDM symbol is thesecond DL OFDM symbol. The first time-frequency resource can occurearlier in time than the second time-frequency resource. The firsttime-frequency resource can be within a first UL symbol in a slot andthe second time-frequency resource can be within a second UL symbol inthe slot, where the first UL symbol can occur before the second ULsymbol. The first time-frequency resource can also be within a firstslot and the second time-frequency resource can also be within a secondslot, where the first slot can occur before the second slot. The DL OFDMcontrol channel can include a DL resource assignment and a RB index fortransmitting data in the DL resource assignment can be selected.According to a possible implementation, the HARQ-ACK can be received ina time-frequency resource based on the selected RB index. The HARQ-ACKfrom the UE can then be received in a time-frequency resource, where theHARQ-ACK can correspond to the transmitted data, and where thetime-frequency resource can at least be based on the selected at leastone DL OFDM symbol. According to another possible implementation, a CCEindex corresponding to the DL control channel candidate can be selectedand the HARQ-ACK can be received in a time-frequency resource based onthe determined CCE index.

According to a related embodiment each control channel candidate can bemapped to REs within multiple OFDM symbols. According to a possibleimplementation, the DL control channel can include one of a plurality ofDL control channels, where each DL control channel can be mapped to REswithin multiple OFDM symbols. Then, a last DL OFDM symbol of theplurality of OFDM symbols corresponding to the DL control channel can beused for determination of a time-frequency resource for the HARQ-ACK,where the HARQ-ACK can correspond to the transmitted data. According toanother possible implementation, data can be transmitted in a resourceassigned by a DL resource assignment in the DL OFDM control channel.Then, the HARQ-ACK can be received in the determined time-frequencyresource in response to transmitting data in the resource assigned bythe DL resource assignment.

FIG. 14 is an example flowchart 1400 illustrating the operation of awireless communication device, such as a network entity, according to apossible embodiment. As in other embodiments, the network entity can bea base station, an access point, a network controller, a mobilitymanagement entity, or any other network entity or combination of networkentities that transmit scheduling information over a wireless wide areanetwork.

At 1410, a number of DL control channel decoding candidates in a set ofDL control channel decoding candidates can be configured for a UE tomonitor the DL control channel decoding candidates. The number of DLcontrol channel decoding candidates can be the actual number of thecandidates. According to a possible implementation, the number of DLcandidates can be configured to be a first number of DL control channelcandidates or a second number of DL control channel candidates, wherefirst number can be smaller than the second number. An indication of thenumber of DL control candidates can be transmitted, such as to a UE. Theindication can be transmitted on a layer higher than a physical layer.The number of control channel decoding candidates in the set of DLcontrol channel candidates can also be transmitted within a slot.

At 1420, a DL resource assignment can be transmitted on one of the DLcontrol channel decoding candidates, the DL resource assignmentindicating a DL resource for transmitting DL data. At 1430, DL data canbe transmitted on the DL resource for transmitting DL data.

At 1440, a HARQ-ACK can be received on an UL time-frequency resource.The UL time-frequency resource can at least be based on the number of DLcontrol decoding candidates. The HARQ-ACK can correspond to thetransmitted DL data. According to a possible implementation, theHARQ-ACK can be received in a first time-frequency resource based on thedetermined number of DL control channel candidates being the firstnumber of DL control channel candidates and the HARQ-ACK can be receivedin a second time-frequency resource based on the determined number of DLcontrol channel candidates being the second number of DL control channelcandidates. The first time-frequency resource can occur earlier in timethan the second time-frequency resource. The first time-frequencyresource can be a first OFDM symbol and the second time-frequencyresource can be a second OFDM symbol. Also, the first time-frequencyresource can be a first slot and the second time-frequency resource canbe a second slot.

FIG. 15 is an example flowchart 1500 illustrating the operation of awireless communication device, such as the UE 110 or any other terminalthat transmits and receives wireless communication signals over awireless wide area network, according to a possible embodiment. At step1510, a number of DL control channel candidates belonging to a set ofcontrol channel decoding candidates can be determined. The number of DLcan be determined to be a first number of DL control channel candidatesor a second number of DL control channel candidates, where the firstnumber can be smaller than the second number. An indication of thenumber of DL control candidates can be received. The indication can bereceived on a layer higher than a physical layer. Also, the number ofcontrol channel decoding candidates can be monitored in the set of DLcontrol channel candidates within a slot.

At 1520, a DL control channel candidate belonging to the set of controlchannel decoding candidates can be decoded. At 1530, a DL resourceassignment can be determined from the decoded DL control channelcandidate. At 1540, data can be received based on the DL resourceassignment. At 1550, a time-frequency resource for transmitting aHARQ-ACK can be determined at least based on the number of DL controlchannel decoding candidates belonging to the set of control channeldecoding candidates.

At 1560, the HARQ-ACK can be transmitted in the determinedtime-frequency resource. The transmitted HARQ-ACK can correspond to thereceived data. The HARQ-ACK can be transmitted in a first time-frequencyresource based on the determined number of DL control channel candidatesbeing the first number of DL control channel candidates. Also, theHARQ-ACK can be transmitted in a second time-frequency resource based onthe determined number of DL control channel candidates being the secondnumber of DL control channel candidates. The first time-frequencyresource can occur earlier in time than the second time-frequencyresource. The first time-frequency resource can be a first OFDM symboland the second time-frequency resource can be a second OFDM symbol.Also, the first time-frequency resource can be a first slot and thesecond time-frequency resource can be a second slot.

It should be understood that, notwithstanding the particular steps asshown in the figures, a variety of additional or different steps can beperformed depending upon the embodiment, and one or more of theparticular steps can be rearranged, repeated or eliminated entirelydepending upon the embodiment. Also, some of the steps performed can berepeated on an ongoing or continuous basis simultaneously while othersteps are performed. Furthermore, different steps can be performed bydifferent elements or in a single element of the disclosed embodiments.

FIG. 16 is an example block diagram of an apparatus 1600, such as awireless communication device that can be a wireless terminal, can be aUE, can be a network entity, such as a base station, or can be any otherwireless communication device, according to a possible embodiment. Theapparatus 1600 can include a housing 1610, a controller 1620 within thehousing 1610, audio input and output circuitry 1630 coupled to thecontroller 1620, a display 1640 coupled to the controller 1620, atransceiver 1650 coupled to the controller 1620, an antenna 1655 coupledto the transceiver 1650, a user interface 1660 coupled to the controller1620, a memory 1670 coupled to the controller 1620, and a networkinterface 1680 coupled to the controller 1620. The apparatus 1600 canperform the methods described in all the embodiments.

The display 1640 can be a viewfinder, a liquid crystal display (LCD), alight emitting diode (LED) display, a plasma display, a projectiondisplay, a touch screen, or any other device that displays information.The transceiver 1650 can include a transmitter and/or a receiver. Theaudio input and output circuitry 1630 can include a microphone, aspeaker, a transducer, or any other audio input and output circuitry.The user interface 1660 can include a keypad, a keyboard, buttons, atouch pad, a joystick, a touch screen display, another additionaldisplay, or any other device useful for providing an interface between auser and an electronic device. The network interface 1680 can be aUniversal Serial Bus (USB) port, an Ethernet port, an infraredtransmitter/receiver, an IEEE 1394 port, a WLAN transceiver, or anyother interface that can connect an apparatus to a network, device, orcomputer and that can transmit and receive data communication signals.The memory 1670 can include a random access memory, a read only memory,an optical memory, a solid state memory, a flash memory, a removablememory, a hard drive, a cache, or any other memory that can be coupledto an apparatus.

The apparatus 1600 or the controller 1620 may implement any operatingsystem, such as Microsoft Windows®, UNIX®, or LINUX®, Android™, or anyother operating system. Apparatus operation software may be written inany programming language, such as C, C++, Java, or Visual Basic, forexample. Apparatus software may also run on an application framework,such as, for example, a Java® framework, a .NET® framework, or any otherapplication framework. The software and/or the operating system may bestored in the memory 1670 or elsewhere on the apparatus 1600. Theapparatus 1600 or the controller 1620 may also use hardware to implementdisclosed operations. For example, the controller 1620 may be anyprogrammable processor. Disclosed embodiments may also be implemented ona general-purpose or a special purpose computer, a programmedmicroprocessor or microprocessor, peripheral integrated circuitelements, an application-specific integrated circuit or other integratedcircuits, hardware/electronic logic circuits, such as a discrete elementcircuit, a programmable logic device, such as a programmable logicarray, field programmable gate-array, or the like. In general, thecontroller 1620 may be any controller or processor device or devicescapable of operating an apparatus and implementing the disclosedembodiments. Some or all of the additional elements of the apparatus1600 can also perform some or all of the operations of the disclosedembodiments.

According to a possible embodiment where the apparatus 1600 is a networkentity, the transceiver 1650 can transmit scheduling information to a UEregarding a DL data channel in a slot. The scheduling information caninclude information regarding at least a set of allocated subcarriers.The DL data channel can require the UE to send an immediate HARQ-ACKfeedback within the slot.

The transceiver 1650 can also transmit DL data by using every x-thsubcarrier among the allocated subcarriers in the last symbol of the DLdata channel A UE can receive only a first part of time-domain samplesout of x of repeated samples in the last symbol of the DL data channel.The controller 1620 can set the value of x based on UE processingcapability. The transceiver 1650 can indicate the value of x to the UE.

According to a possible embodiment where the apparatus 1600 is a UE, thetransceiver 1650 can receive scheduling information from a networkentity. The scheduling information can pertain to a DL data channel in aslot. The scheduling information can include information regarding atleast a set of allocated subcarriers and the DL data channel can requirethe UE to send an immediate HARQ-ACK feedback within the slot. Thetransceiver 1650 can receive DL data by using every x-th subcarrieramong the allocated subcarriers in the last symbol of the DL datachannel. The controller 1620 can process the DL data. The transceiver1650 may receive only a first part of time-domain samples out of xrepeated samples in the last symbol of the DL data channel. Thetransceiver 1650 can transmit a HARQ-ACK in response to receiving the DLdata.

According to a possible embodiment, where the apparatus 1600 is a UE,the transceiver 1650 can receive scheduling information to transmit afirst physical uplink channel within a slot, where the slot can includea plurality of symbols. The slot can include the first physical uplinkchannel and a second physical uplink channel. The first physical uplinkchannel can be shorter in duration than the second physical uplinkchannel.

The controller 1620 can determine one or more allocated RBs for thefirst physical uplink channel based on a sub-band group and one or moreRBGs within the sub-band group. The sub-band group can include one ormore sub-bands, each sub-band can include one or more RBGs, each RBG caninclude one or more RBs, and a RB can include one or more contiguous REsin the frequency domain. The one or more sub-bands in the sub-band groupcan be distributed over the apparatus's configured operating BW. Theapparatus's configured operating BW can include at least one sub-bandgroup. A system BW including the apparatus's configured operating BW caninclude at least one sub-band group. The transceiver 1650 can transmitthe first physical uplink channel in the determined one or moreallocated RBs in the slot.

According to a possible implementation, a slot can include a first PUCCHand a second PUCCH, where the first PUCCH can be shorter in durationthan the second PUCCH. The first physical uplink channel can be thefirst PUCCH. The first PUCCH can have one of the following short PUCCHformats based on UCI type and sizes:

-   -   Format 1: SR,    -   Format 1a: 1-bit HARQ-ACK,    -   Format 1b: 2-bit HARQ-ACK, or    -   Format 2: combination of CSI and HARQ-ACK.

According to a possible embodiment where the apparatus 1600 is a UE, thecontroller 1620 can decode a DL control channel candidate. Thecontroller 1620 can decode the DL control channel candidate in a slot.The controller 1620 can determine which DL OFDM symbol the decoded DLcontrol channel candidate is received in. For example, the controller1620 can determine the DL OFDM symbol in the slot in which the DLcontrol channel candidate is decoded. The controller 1620 can determinea DL resource assignment from the decoded DL control channel candidate.

The transceiver 1650 can receive data based on the DL resourceassignment. The controller 1620 can determine a time-frequency resourcefor transmitting a HARQ-ACK at least based on the determined DL OFDMsymbol. The UL OFDM symbol in the slot for transmitting HARQ-ACK can bedetermined at least based on the determined DL OFDM symbol. Thetime-frequency resource for transmitting HARQ-ACK can be determined tobe a subsequent slot for transmitting HARQ-ACK at least based on thedetermined DL OFDM symbol. The transceiver 1650 can transmit theHARQ-ACK in the determined time-frequency resource, where thetransmitted HARQ-ACK can correspond to the received data. The HARQ-ACKcan be transmitted in the determined UL OFDM symbol. The HARQ-ACK canalso be transmitted in the determined subsequent slot.

According to a possible implementation, determining a DL OFDM symbol thedecoded DL control candidate is received in can be based on determiningthe DL OFDM symbol from one of a first DL OFDM symbol and a second OFDMDL symbol corresponding to the decoded DL control channel candidate. Thefirst OFDM symbol can occur earlier in time than the second OFDM symbol.The transceiver 1650 can transmit the HARQ-ACK in a first time-frequencyresource if the determined DL OFDM symbol is the first DL OFDM symbol.The transceiver 1650 can transmit the HARQ-ACK in a secondtime-frequency resource if the determined DL OFDM symbol is the secondDL OFDM symbol. The first time-frequency resource can occur earlier intime than the second time-frequency resource. The first time-frequencyresource can be within a first UL symbol in a slot and the secondtime-frequency resource can be within a second UL symbol in the slot,where the first UL symbol can occur before the second UL symbol. Thefirst time-frequency resource can also be within a first slot and thesecond time-frequency resource can be within a second slot, where thefirst slot can occur before the second slot.

The controller 1620 can determine a RB index for receiving data from theDL resource assignment. The determined time-frequency resource fortransmitting HARQ-ACK can be based on determining the time-frequencyresource for transmitting HARQ-ACK based on the determined RB index. Thecontroller 1620 can determine a CCE index corresponding to the DLcontrol channel candidate. The determined time-frequency resource fortransmitting HARQ-ACK can be based on determining the time-frequencyresource for transmitting HARQ-ACK based on the determined CCE index.

According to another possible implementation, each control channelcandidate can be mapped to REs within multiple OFDM symbols. The DLcontrol channel candidate can be one of a plurality of DL controlchannel candidates, where each DL control channel candidate can bemapped to REs within multiple OFDM symbols. Determining a DL OFDM symbolcan be based on determining a last DL OFDM symbol of multiple OFDMsymbols corresponding to the decoded DL control channel candidate.

Data can be received by the transceiver 1650 in a resource assigned bythe DL resource assignment. Then the HARQ-ACK can be transmitted by thetransceiver 1650 in the determined time-frequency resource in responseto receiving the data based on the DL resource assignment.

According to a possible embodiment where the apparatus 1600 is a UE, thecontroller 1620 can monitor the number of control channel decodingcandidates in the set of DL control channel candidates within a slot.The controller 1620 can determine a number of DL control channelcandidates belonging to a set of control channel decoding candidates.The number of DL control channel candidates can be determined to be afirst number of DL control channel candidates or a second number of DLcontrol channel candidates, where the first number can be smaller thanthe second number. The controller 1620 can decode a DL control channelcandidate belonging to the set of control channel decoding candidates.The controller 1620 can determine a DL resource assignment from thedecoded DL control channel candidate.

The transceiver 1650 can receive data based on the DL resourceassignment. In response to receiving the data, the controller 1620 candetermine a time-frequency resource for transmitting a HARQ-ACK at leastbased on the number of DL control channel decoding candidates belongingto the set of control channel decoding candidates. The transceiver 1650can transmit the HARQ-ACK in the determined time-frequency resource,where the transmitted HARQ-ACK can correspond to the received data. TheHARQ-ACK can be transmitted in a first time-frequency resource based onthe determined number of DL control channel candidates being the firstnumber. The HARQ-ACK can be transmitted in a second time-frequencyresource based on the determined number of DL control channel candidatesbeing the second number. The first time-frequency resource can occurearlier in time than the second time-frequency resource.

According to a possible embodiment, where the apparatus 1600 is anetwork entity, the controller 1620 can configure a number of DL controlchannel decoding candidates in a set of DL control channel decodingcandidates for a UE to monitor the DL control channel decodingcandidates. Configuring a number of DL control channel candidates caninclude configuring the number to be a first number of DL controlchannel candidates or a second number of DL control channel candidates,where the first number can be smaller than the second number. Thetransceiver 1650 can transmit an indication of the number of DL controlcandidates, such as to a UE.

The transceiver 1650 can transmit a DL resource assignment on one of theDL control channel decoding candidates, such as to a UE. The DL resourceassignment can indicate a DL resource for transmitting DL data. Thetransceiver 1650 can transmit DL data on the DL resource fortransmitting DL data, such as to a UE. The transceiver 1650 can receivea HARQ-ACK on an UL time-frequency resource. The UL time-frequencyresource can at least be based on the number of DL control decodingcandidates. The HARQ-ACK can correspond to the transmitted DL data. Thetransceiver 1650 can receive the HARQ-ACK in a first time-frequencyresource based on the determined number of DL control channel candidatesbeing the first number. The transceiver 1650 can receive the HARQ-ACK ina second time-frequency resource based on the determined number of DLcontrol channel candidates being the second number. The firsttime-frequency resource can occur earlier in time than the secondtime-frequency resource.

The methods of this disclosure can be implemented on a programmedprocessor. However, the controllers, flowcharts, and modules may also beimplemented on a general purpose or special purpose computer, aprogrammed microprocessor or microcontroller and peripheral integratedcircuit elements, an integrated circuit, a hardware electronic or logiccircuit such as a discrete element circuit, a programmable logic device,or the like. In general, any device on which resides a finite statemachine capable of implementing the flowcharts shown in the figures maybe used to implement the processor functions of this disclosure.

While this disclosure has been described with specific embodimentsthereof, it is evident that many alternatives, modifications, andvariations will be apparent to those skilled in the art. For example,various components of the embodiments may be interchanged, added, orsubstituted in the other embodiments. Also, all of the elements of eachfigure are not necessary for operation of the disclosed embodiments. Forexample, one of ordinary skill in the art of the disclosed embodimentswould be enabled to make and use the teachings of the disclosure bysimply employing the elements of the independent claims. Accordingly,embodiments of the disclosure as set forth herein are intended to beillustrative, not limiting. Various changes may be made withoutdeparting from the spirit and scope of the disclosure.

In this document, relational terms such as “first,” “second,” and thelike may be used solely to distinguish one entity or action from anotherentity or action without necessarily requiring or implying any actualsuch relationship or order between such entities or actions. The phrase“at least one of,” “at least one selected from the group of,” or “atleast one selected from” followed by a list is defined to mean one,some, or all, but not necessarily all of, the elements in the list. Theterms “comprises,” “comprising,” “including,” or any other variationthereof, are intended to cover a non-exclusive inclusion, such that aprocess, method, article, or apparatus that comprises a list of elementsdoes not include only those elements but may include other elements notexpressly listed or inherent to such process, method, article, orapparatus. An element proceeded by “a,” “an,” or the like does not,without more constraints, preclude the existence of additional identicalelements in the process, method, article, or apparatus that comprisesthe element. Also, the term “another” is defined as at least a second ormore. The terms “including,” “having,” and the like, as used herein, aredefined as “comprising.” Furthermore, the background section is writtenas the inventor's own understanding of the context of some embodimentsat the time of filing and includes the inventor's own recognition of anyproblems with existing technologies and/or problems experienced in theinventor's own work.

We claim:
 1. A method in a user equipment, the method comprising:decoding a downlink control channel candidate; determining whichdownlink orthogonal frequency division multiplexing symbol the decodeddownlink control channel candidate is received in; determining adownlink resource assignment from the decoded downlink control channelcandidate; receiving data based on the downlink resource assignment;determining a time-frequency resource for transmitting a hybridautomatic repeat request acknowledgement at least based on thedetermined downlink orthogonal frequency division multiplexing symbol;and transmitting the hybrid automatic repeat request acknowledgement inthe determined time-frequency resource, where the transmitted hybridautomatic repeat request acknowledgement corresponds to the receiveddata.
 2. The method according to claim 1, wherein decoding comprisesdecoding the downlink control channel candidate in a slot, whereindetermining which downlink orthogonal frequency division multiplexingsymbol the decoded downlink control candidate is received in furthercomprises determining the downlink orthogonal frequency divisionmultiplexing symbol is in the slot in which the downlink control channelcandidate is decoded, wherein determining a time-frequency resource fortransmitting hybrid automatic repeat request acknowledgement at leastbased on the determined downlink orthogonal frequency divisionmultiplexing symbol further comprises determining an uplink orthogonalfrequency division multiplexing symbol in the slot for transmittinghybrid automatic repeat request acknowledgement at least based on thedetermined downlink orthogonal frequency division multiplexing symbol,and wherein transmitting the hybrid automatic repeat requestacknowledgement comprises transmitting the hybrid automatic repeatrequest acknowledgement in the determined uplink orthogonal frequencydivision multiplexing symbol, where the transmitted hybrid automaticrepeat request acknowledgement corresponds to the received data.
 3. Themethod according to claim 1, wherein decoding comprises decoding thedownlink control channel candidate in a slot, wherein determining thedownlink orthogonal frequency division multiplexing symbol the decodeddownlink control candidate is received in further comprises determiningthe downlink orthogonal frequency division multiplexing symbol is in theslot in which the downlink control channel candidate is decoded, whereindetermining a time-frequency resource for transmitting hybrid automaticrepeat request acknowledgement at least based on the determined downlinkorthogonal frequency division multiplexing symbol further comprisesdetermining a subsequent slot for transmitting hybrid automatic repeatrequest acknowledgement at least based on the determined downlinkorthogonal frequency division multiplexing symbol, and whereintransmitting the hybrid automatic repeat request acknowledgementcomprises transmitting the hybrid automatic repeat requestacknowledgement in the determined subsequent slot, where the transmittedhybrid automatic repeat request acknowledgement corresponds to thereceived data.
 4. The method according to claim 1, wherein determining adownlink orthogonal frequency division multiplexing symbol the decodeddownlink control candidate is received in further comprises determiningthe downlink orthogonal frequency division multiplexing symbol from oneof a first downlink orthogonal frequency division multiplexing symboland a second orthogonal frequency division multiplexing downlink symbolcorresponding to the decoded downlink control channel candidate, whereinthe first orthogonal frequency division multiplexing symbol occursearlier in time than the second orthogonal frequency divisionmultiplexing symbol, wherein transmitting the hybrid automatic repeatrequest acknowledgement comprises: transmitting the hybrid automaticrepeat request acknowledgement in a first time-frequency resource if thedetermined downlink orthogonal frequency division multiplexing symbol isthe first downlink orthogonal frequency division multiplexing symbol;and transmitting the hybrid automatic repeat request acknowledgement ina second time-frequency resource if the determined downlink orthogonalfrequency division multiplexing symbol is the second downlink orthogonalfrequency division multiplexing symbol, and wherein the firsttime-frequency resource occurs earlier in time than the secondtime-frequency resource.
 5. The method according to claim 4, wherein thefirst time-frequency resource is within a first uplink symbol in a slotand the second time-frequency resource is within a second uplink symbolin the slot, where the first uplink symbol occurs before the seconduplink symbol.
 6. The method according to claim 4, wherein the firsttime-frequency resource is within a first slot and the secondtime-frequency resource is within a second slot, where the first slotoccurs before the second slot.
 7. The method according to claim 4,further comprising determining a resource block index for receiving datafrom the downlink resource assignment, wherein determining thetime-frequency resource for transmitting hybrid automatic repeat requestacknowledgement further comprises determining the time-frequencyresource for transmitting hybrid automatic repeat requestacknowledgement based on the determined resource block index.
 8. Themethod according to claim 4, further comprising determining a controlchannel element index corresponding to the downlink control channelcandidate, wherein determining the time-frequency resource fortransmitting hybrid automatic repeat request acknowledgement furthercomprises determining the time-frequency resource for transmittinghybrid automatic repeat request acknowledgement based on the determinedcontrol channel element index.
 9. The method according to claim 1,wherein the downlink control channel candidate comprises one of aplurality of downlink control channel candidates, where each downlinkcontrol channel candidate can be mapped to resource elements withinmultiple orthogonal frequency division multiplexing symbols, and whereindetermining a downlink orthogonal frequency division multiplexing symbolcomprises determining a last downlink orthogonal frequency divisionmultiplexing symbol of multiple orthogonal frequency divisionmultiplexing symbols corresponding to the decoded downlink controlchannel candidate.
 10. The method according to claim 1, whereinreceiving data comprises receiving data in a resource assigned by thedownlink resource assignment, and wherein transmitting the hybridautomatic repeat request acknowledgement in the determinedtime-frequency resource comprises transmitting the hybrid automaticrepeat request acknowledgement in the determined time-frequency resourcein response to receiving the data based on the downlink resourceassignment.
 11. An apparatus comprising: a controller that decodes adownlink control channel candidate, determines which downlink orthogonalfrequency division multiplexing symbol the decoded downlink controlchannel candidate is received in, and determines a downlink resourceassignment from the decoded downlink control channel candidate; and atransceiver coupled to the controller, where the transceiver receivesdata based on the downlink resource assignment, wherein the controllerdetermines a time-frequency resource for transmitting a hybrid automaticrepeat request acknowledgement at least based on the determined downlinkorthogonal frequency division multiplexing symbol, and wherein thetransceiver transmits the hybrid automatic repeat requestacknowledgement in the determined time-frequency resource, where thetransmitted hybrid automatic repeat request acknowledgement correspondsto the received data.
 12. The apparatus according to claim 11, whereindecoding comprises decoding the downlink control channel candidate in aslot, wherein determining the downlink orthogonal frequency divisionmultiplexing symbol the decoded downlink control candidate is receivedin further comprises determining the downlink orthogonal frequencydivision multiplexing symbol is in the slot in which the downlinkcontrol channel candidate is decoded, wherein determining atime-frequency resource for transmitting hybrid automatic repeat requestacknowledgement at least based on the determined downlink orthogonalfrequency division multiplexing symbol further comprises determining anuplink orthogonal frequency division multiplexing symbol in the slot fortransmitting hybrid automatic repeat request acknowledgement at leastbased on the determined downlink orthogonal frequency divisionmultiplexing symbol, and wherein transmitting the hybrid automaticrepeat request acknowledgement comprises transmitting the hybridautomatic repeat request acknowledgement in the determined uplinkorthogonal frequency division multiplexing symbol, where the transmittedhybrid automatic repeat request acknowledgement corresponds to thereceived data.
 13. The apparatus according to claim 11, wherein decodingcomprises decoding the downlink control channel candidate in a slot,wherein determining the downlink orthogonal frequency divisionmultiplexing symbol the decoded downlink control candidate is receivedin further comprises determining the downlink orthogonal frequencydivision multiplexing symbol is in the slot in which the downlinkcontrol channel candidate is decoded, wherein determining atime-frequency resource for transmitting hybrid automatic repeat requestacknowledgement at least based on the determined downlink orthogonalfrequency division multiplexing symbol further comprises determining asubsequent slot for transmitting hybrid automatic repeat requestacknowledgement at least based on the determined downlink orthogonalfrequency division multiplexing symbol, and wherein transmitting thehybrid automatic repeat request acknowledgement comprises transmittingthe hybrid automatic repeat request acknowledgement in the determinedsubsequent slot, where the transmitted hybrid automatic repeat requestacknowledgement corresponds to the received data.
 14. The apparatusaccording to claim 11, wherein determining a downlink orthogonalfrequency division multiplexing symbol the decoded downlink controlcandidate is received in further comprises determining the downlinkorthogonal frequency division multiplexing symbol from one of a firstdownlink orthogonal frequency division multiplexing symbol and a secondorthogonal frequency division multiplexing downlink symbol correspondingto the decoded downlink control channel candidate, wherein the firstorthogonal frequency division multiplexing symbol occurs earlier in timethan the second orthogonal frequency division multiplexing symbol,wherein transmitting the hybrid automatic repeat request acknowledgementcomprises: transmitting the hybrid automatic repeat requestacknowledgement in a first time-frequency resource if the determineddownlink orthogonal frequency division multiplexing symbol is the firstdownlink orthogonal frequency division multiplexing symbol, andtransmitting the hybrid automatic repeat request acknowledgement in asecond time-frequency resource if the determined downlink orthogonalfrequency division multiplexing symbol is the second downlink orthogonalfrequency division multiplexing symbol, and wherein the firsttime-frequency resource occurs earlier in time than the secondtime-frequency resource.
 15. The apparatus according to claim 14,wherein the first time-frequency resource is within a first uplinksymbol in a slot and the second time-frequency resource is within asecond uplink symbol in the slot, where the first uplink symbol occursbefore the second uplink symbol.
 16. The apparatus according to claim14, wherein the first time-frequency resource is within a first slot andthe second time-frequency resource is within a second slot, where thefirst slot occurs before the second slot.
 17. The apparatus according toclaim 14, wherein the controller determines a resource block index forreceiving data from the downlink resource assignment, and whereindetermining the time-frequency resource for transmitting hybridautomatic repeat request acknowledgement further comprises determiningthe time-frequency resource for transmitting hybrid automatic repeatrequest acknowledgement based on the determined resource block index.18. The apparatus according to claim 14, wherein the controllerdetermines a control channel element index corresponding to the downlinkcontrol channel candidate, and wherein determining the time-frequencyresource for transmitting hybrid automatic repeat requestacknowledgement further comprises determining the time-frequencyresource for transmitting hybrid automatic repeat requestacknowledgement based on the determined control channel element index.19. The apparatus according to claim 11, wherein the downlink controlchannel candidate comprises one of a plurality of downlink controlchannel candidates, where each downlink control channel candidate can bemapped to resource elements within multiple orthogonal frequencydivision multiplexing symbols, and wherein determining a downlinkorthogonal frequency division multiplexing symbol comprises determininga last downlink orthogonal frequency division multiplexing symbol ofmultiple orthogonal frequency division multiplexing symbolscorresponding to the decoded downlink control channel candidate.
 20. Theapparatus according to claim 11, wherein receiving data comprisesreceiving data in a resource assigned by the downlink resourceassignment, and wherein transmitting the hybrid automatic repeat requestacknowledgement in the determined time-frequency resource comprisestransmitting the hybrid automatic repeat request acknowledgement in thedetermined time-frequency resource in response to receiving the databased on the downlink resource assignment.